Current Benchmark
<?php
$template = '
<html><head><title>{$title}</title></head><body><?php if(true) { ?>TRUE!<?php } else { ?>FALSE!<?php } ?></body></html>
';
$array = $array;
$title = 'Page Title';
eval('echo "'.strtr($template, $array).'";');
?>
vs.
<?php
$template = '
<html><head><title>{$title}</title></head><body><?php if(true) { ?>TRUE!<?php } else { ?>FALSE!<?php } ?></body></html>
';
$array = $array;
$title = 'Page Title';
foreach ($array as $f => $re)
$template = str_replace($f, $re, $template);
eval('echo "'.$template.'";');
?>
Conclusion
After an average of 6000 cycles, the fastest option is Benchmark 1!
<?php
$template = '
<html><head><title>{$title}</title></head><body><?php if(true) { ?>TRUE!<?php } else { ?>FALSE!<?php } ?></body></html>
';
$array = $array;
$title = 'Page Title';
eval('echo "'.strtr($template, $array).'";');
?>